The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 15, 1995
Filed:
Jun. 10, 1994
Masanori Fukuhira, Takasaki, JP;
Hirofumi Fukuoka, Annaka, JP;
Yoshiharu Konya, Annaka, JP;
Masaki Watanabe, Annaka, JP;
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
In a method for preparing a high .alpha.-type silicon nitride powder by adding to and mixing with metallic silicon powder a copper catalyst and nitriding the mixture in a non-oxidizing gas atmosphere containing nitrogen or ammonia at 1,000.degree. to 1,500.degree. C., the amount of copper catalyst is limited to from 0.05 % to less than 0.5 % by weight of copper based on the weight of the metallic silicon. There is obtained silicon nitride powder of high purity at low cost and high efficiency since the copper catalyst can be efficiently removed from the silicon nitride powder through conventional acid treatment.